Mid-Ohio race did not go well

Doug MacRae · Jul 28, 2014

I was revving the motor to around 6500 that day, I had noticed that there was a slight vibration or something didn't feel right earlier in the weekend when I revved it right to 7000 and I had mentioned it to Herb before it let go. The motor was running beautiful though, making lots of power. I am just guessing at the speed but it would be somewhere around there. The only completely accurate idea of the speed of the bike I have is when I got radar gunned at Daytona at 129mph. The theoretical top speed of gearing / revs vs tire diameter formula is a bit optimistic I believe because the theoretical speed I should have been doing there is 142mph with that gearing

Fullauto · Jul 28, 2014

I think that some people think of large (and small!) engine parts in terms of rigidity. A lifetime of playing with guns and the tuning thereof for accuracy has taught me to think of parts as fluid, and taking into account that movement in the build. Norton engines are as rubbery as you get!

comnoz · Jul 28, 2014

Doug MacRae said:
I was revving the motor to around 6500 that day, I had noticed that there was a slight vibration or something didn't feel right earlier in the weekend when I revved it right to 7000 and I had mentioned it to Herb before it let go. The motor was running beautiful though, making lots of power. I am just guessing at the speed but it would be somewhere around there. The only completely accurate idea of the speed of the bike I have is when I got radar gunned at Daytona at 129mph. The theoretical top speed of gearing / revs vs tire diameter formula is a bit optimistic I believe because the theoretical speed I should have been doing there is 142mph with that gearing

It's because of tire slip. I noticed the same thing a Daytona several years ago. They told me 10 mph slip at 150 would be common. Jim

jseng1 · Aug 3, 2014

Here's an all aluminum rod that blew up in a very expensive race bike. The caps and/or the rod bolts gave out. The problem with all Aluminum rods with aluminum caps is that they expand too much with heat and the clearance to the journal increases too much allowing the oil pressure to drop. Then the shell bearings start to wear and the hammering can break the rod bolts.

Mid-Ohio race did not go well

Doug MacRae

Fullauto

comnoz

jseng1

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